Stockholders' Equity - Common Stock Shares Activity (Details) - shares shares in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2024 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2023 |
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||
| Purchases of treasury stock | (10.2) | (14.4) | ||
| Common Stock | Class A | ||||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||
| Balance at beginning of period | 924.2 | 941.4 | 927.3 | 948.4 |
| Purchases of treasury stock | (5.8) | (6.5) | (10.2) | (14.4) |
| Share-based payments | 0.1 | 0.9 | 1.3 | 1.7 |
| Conversion of Class B to Class A common stock | 0.0 | 0.1 | 0.1 | 0.2 |
| Balance at end of period | 918.5 | 935.9 | 918.5 | 935.9 |
| Common Stock | Class B | ||||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ||||
| Balance at beginning of period | 7.1 | 7.5 | 7.2 | 7.6 |
| Purchases of treasury stock | 0.0 | 0.0 | 0.0 | 0.0 |
| Share-based payments | 0.0 | 0.0 | 0.0 | 0.0 |
| Conversion of Class B to Class A common stock | 0.0 | (0.1) | (0.1) | (0.2) |
| Balance at end of period | 7.1 | 7.4 | 7.1 | 7.4 |